Boris Johnson has "earned" the right to be given greater tax powers by the coalition government, his policy director, Anthony Browne, has said.

Browne claims London is currently "the most fiscally infantilised big city on earth" and insisted its mayor had "more than earned" the right to have his powers increased.

Johnson's only tax-raising power over Londoners is the London precept, levied on Londoners' council tax, which he has chosen to freeze for two successive years.

Prior to the Tories forming a coalition government in May, Johnson had described his freeze on the precept as a sign of "Conservative government in action".

But in an article for the trade journal Public Servant, Browne suggested that Johnson wanted more scope to impose levies.

He contrasted the mayor's existing powers, which allow him to raise just 7% of his own income, with those of the mayors of major cities such as New York and Tokyo, which raise 50% and 80% respectively.

Browne laid out the case for greater fiscal powers for the mayoralty and described the devolution for London introduced under Labour in 2000 as "half-baked".

Johnson was in talks with the Conservative party about power-boosting measures prior to the general election.

Last month, he published a document suggesting a range of amendments to enhance the devolution deal for London, which made no mention of his desire for greater tax powers.

His published proposals, billed as giving the mayoralty more accountability, include bringing the economic London Development Agency (LDA) arm into the Greater London authority, taking control of the Homes and Communities Agency for London, and ending ringfenced grants from government to give him more "financial freedom".

Highlighting the extra powers already requested, Browne wrote: "We have one big ask – more power over taxation ... we have to go cap in hand to central government, both for money and permission.

"There is a fundamental issue here about so called buoyancy – our revenues don't increase as the economy grows.

"Although we are statutorily responsible for the economic development of London, we get no financial benefit from it. We can't invest in measures to boost the London economy and reap the rewards of economic growth.

"Both the previous and current incumbent believe we need more financial autonomy in London, with the mayor getting greater tax powers. It would require a leap of trust from Whitehall, but we have more than earned it."

Browne was unavailable for further comment, but his suggestion was welcomed by Darren Johnson, a Green London assembly member.

He said the mayor should also take back control of the setting of business rates for the capital, adding: "A city like London should be given more power to raise its own funds, rather than going cap in hand to the government all the time.

"The mayor and assembly should be given the power to raise a precept on income tax, like the Scottish parliament, rather than relying on a less than fair precept on the council tax."

The Department of Communities and Local Government, which is expected to draw up a green or white paper on the devolution of further powers to London and local government ahead of the localism bill, due in autumn, was unable to provide a comment.